Interplay of magnetic ordering and charge transport in a distorted ScAl$_3$C$_3$-type GdZn$_3$As$_3$

TL;DR

This study reports the synthesis and detailed characterization of GdZn3As3, a new distorted orthorhombic $RM_3X_3$ compound exhibiting ferromagnetism, metallic conductivity, and unusual Hall effects, offering insights into magnetic interactions in low-carrier-density systems.

Contribution

It introduces GdZn3As3 as a novel distorted $RM_3X_3$ compound with unique magnetic and electronic properties, expanding the understanding of magnetic ordering in this family.

Findings

GdZn3As3 undergoes ferromagnetic transition at 6.3 K.

Displays metallic behavior with negative magnetoresistance.

Shows nonlinear anomalous Hall effect and possible additional magnetic transitions.

Abstract

We present the synthesis and characterization of GdZn$_3$As$_3$, a previously unreported variant of the $RM_3X_3$ family ($R$ = lanthanides; $M$ = Zn, Cd; $X$ = P, As), prepared in both single-crystal and polycrystalline forms. Unlike other $RM_3X_3$ compounds that crystallize in undistorted hexagonal structures, GdZn$_3$As$_3$ adopts a distorted ScAl$_3$C$_3$-type orthorhombic structure with $Cmcm$ space group. Magnetic measurements demonstrate that GdZn$_3$As$_3$ undergoes a ferromagnetic transition at the Curie temperature ($T_{\mathrm{C}}$) of 6.3~K, which is unique among known $RM_3X_3$ materials. This magnetic transition is further confirmed by specific heat and electrical resistivity measurements. GdZn$_3$As$_3$ displays metallic behavior with a pronounced resistivity peak near $T_{\mathrm{C}}$, which is strongly suppressed by magnetic fields, leading to significant negative magnetoresistance. Hall effect measurements reveal a low carrier density and a clear nonlinear anomalous Hall effect in GdZn$_3$As$_3$. Furthermore, both specific heat and resistivity data suggest the presence of additional magnetic transition(s) below $T_{\mathrm{C}}$, requiring further investigation. These results demonstrate that GdZn$_3$As$_3$ possesses distinct structural, magnetic, and electronic transport properties within the $RM_3X_3$ family, establishing it as an exceptional platform for investigating competing magnetic interactions in low-carrier-density rare-earth triangular-lattice systems.